Disposable self-shielding unit dose syringe guard

ABSTRACT

An improved guard for a medical cartridge, such as a unit dose pre-filled glass syringe, comprising a body for receiving the cartridge, and a shield slidably attached to the body which are pre-assembled and ready to receive a cartridge therein. The body has a mechanism on a proximal end thereof which holds the cartridge therein. The body and shield have cooperating detents and detent pockets which allow the shield to be directed distally, from an unguarded position in which the needle on the cartridge is uncovered for delivery of medication, to a guarded position in which the needle is permanently covered for disposal. The body may also include a substantially rectangular-shaped finger grip on its proximal end for receiving a similarly shaped proximal flange on the cartridge, whereby the cartridge is received in a predetermined orientation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/023,587,filed Dec. 17, 2001, which is a continuation of co-pending applicationSer. No. 09/634,689, now U.S. Pat. No. 6,344,032, filed Aug. 8, 2000,which is a continuation of application Ser. No. 08/942,938 filed on Oct.2, 1997, now U.S. Pat. No. 6,159,184, which is a continuation-in-part ofapplication Ser. No. 08/814,199, filed Mar. 10, 1997, now U.S. Pat. No.6,171,283, all of which are fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to syringes, and moreparticularly to an improved syringe guard for a unit dose cartridge orpre-filled syringe and including a shield for covering the needlethereof after medication is dispensed from the syringe.

BACKGROUND OF THE INVENTION

Medication is often dispensed using a unit dose medical cartridge, suchas an ampule, vial or syringe, and a syringe holder, injector oradapter. The cartridge typically has a barrel with a needle at one endand a plunger at the other end. Such cartridges are often referred to as“pre-filled syringes” because they contain a specific dosage or volumeof medication when they are initially provided, as compared toconventional syringes which are furnished empty and filled by the userprior to use. Alternatively, the medical cartridge may include a rubberstopper instead of a needle, or may include a piston rather than aplunger on the other end. The syringe adapter is typically a hollow bodyadapted to hold the cartridge, including a plunger to engage and movethe piston in the cartridge.

Because of the threat of communicable diseases, a number of syringes andadapters have been developed to prevent accidental needle sticks orinadvertent reuse of needle devices. Many of these devices, however, arenot easy to use or are complicated to manufacture, resulting in lesseffective disposable syringe devices.

For example, U.S. Pat. No. 5,569,211 discloses a syringe that allows theneedle of the syringe to be withdrawn into the barrel of the syringeafter medication is dispensed from it. This device, however, is aspecially designed substitute for a conventional syringe, and cannot beused to hold commercially available pre-filled syringes.

U.S. Pat. No. 5,522,812 discloses a complicated syringe shield devicefor holding a conventional cartridge not having its own needle. Thedevice has a number of complicated parts, including a cylindrical body,a double needle assembly, a cylindrical shield, a special collar pieceallowing the shield to be drawn over the needle and locked, and aplunger assembly, resulting in a device that is potentially difficultand expensive to manufacture. The device also requires two hands tooperate, one to hold the body, and one to rotate the shield into thelocked position, which may be inconvenient to the medical professionalusing the device.

Another consideration with unit dose cartridges and pre-filled syringesis that they are often made from glass, particularly for holding certainvaccines or biotech drugs where concern about micro-organisms or othercontaminants is most critical. Glass cartridges and pre-filled syringesare very fragile and often break during transportation or use. Someexisting adapters may not adequately protect the syringe containedtherein from such risks. Others provide greater protection for thecartridge, but may obstruct the professional's view of the syringe whenthe device is being used, hampering monitoring of the medication beingdelivered.

Therefore, there is a need for an improved safety syringe which isinexpensive and simple to manufacture.

In addition, there is a need for a safety syringe guarding mechanismwhich provides improved protection for the cartridge or pre-filledsyringe therein, but allows effective observation of the syringe and themedication being dispensed.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a guard or adapter for a medicalcartridge, such as a unit dose cartridge or pre-filled syringe, that isused to inject medication or other drugs into a patient. Generally, theguard comprises two parts, namely a housing or body for receiving andholding the cartridge, and a protective case or shield slidably attachedto the body. In addition, for a cartridge provided without its ownplunger, an embodiment of the guard includes a finger grip plug that isattached to the body and a plunger connectable to the piston of thecartridge. The various parts are generally molded from a suitableplastic, such as polypropylene, K-Resin® (synthetic resinous polymers ofbutadiene and styrene), or polycarbonate, having a clear finish.

The body generally includes two elongate rails or similar structuresdefining a substantially rectangular shape, having a cavity thereinadapted to receive a medical cartridge or a pre-filled syringe. The bodyhas an open proximal end communicating with the cavity, a distal endwith an opening through it, and possibly a collar molded to the distalend. The body may also include a plurality of tabs or ribs extendingalong a portion of the cavity adapted to engage the barrel of acartridge received therein.

The protective case or shield is a tubular member adapted to slidablyfit on the body, having open proximal and distal ends. One or moreelongate windows are formed in the shield, allowing observation of thecartridge or pre-filled syringe held within the body. One or morewindows, preferably the same windows used for viewing the cartridge,also cooperate with a stop tab or tabs molded on the body, therebylimiting the relative sliding relationship of the shield and the body.In addition, the shield includes a set of detents, preferably comprisinga pair of detent arms and protruding detents molded into the proximalend of the shield. The detents cooperate with one or more sets of detentpockets molded into the body to lock the shield in relation to the body.

The shield is generally provided pre-assembled on the body, preferablyby inserting the body into the shield until the stop tabs on the bodycommunicate with the elongate windows on the shield. The shield may thenslide in relation to the body between a proximal or unguarded positionand a distal or guarded position, defined by the length of the windowsin the shield. The guard is generally provided with the shield in theproximal or unguarded position, wherein the stop tabs abut the distaledges of the windows. Alternatively, the proximal travel of the shieldmay be limited by the detent arms abutting a finger grip on the body. Inthe unguarded position, the detents on the shield preferably engage aset of proximal detent pockets on the body, holding the shield inrelation to the body.

Generally, after the cartridge or pre-filled syringe in the guard hasbeen used to deliver its medication, the shield is moved distally untilit reaches the guarded position. In the guarded position, the stop tabson the body abut the proximal edges of the windows, preventing furtherdistal movement. As the shield is moved, the detents on the shield leavethe proximal detent pockets, preferably because of sloping edges on theproximal detent pockets, and slide along the body until they enter a setof distal detent pockets when the shield reaches the guarded position.The distal detent pockets may have blunt or oblique proximal edges,which prevent the shield from being returned proximally, and therebysubstantially lock the shield in the guarded position for disposal.Preferably, the proximal edges of the detent pockets are inclined at anangle corresponding substantially to the proximal edges of the detentsto maximize bearing surface engagement therebetween.

In a first preferred embodiment, the guard has only two parts, namely abody and a shield, which are pre-assembled in the unguarded positionready to receive a cartridge. In this embodiment, the body includes afinger grip integrally molded onto its proximal end, preferably defininga “T” shape, having locking detents formed on the finger grip. Acartridge, preferably and typically a conventional unit dose pre-filledsyringe including a needle and needle cover on its distal end and aplunger and flange on its proximal end, is inserted into the proximalend of the body until it is fully encapsulated within the cavity. Oncefully inserted, the proximal end of the pre-filled syringe engages thelocking detents on the finger grip, substantially permanently lockingthe pre-filled syringe into the guard. Once locked into the guard, theneedle and its cover on the pre-filled syringe extend at least partiallythrough the distal openings in the body and shield and preferably beyondtheir distal ends.

After medication is dispensed, the shield is slid into the guardedposition, using one or two hands, preferably only requiring one hand.During use, the index and middle fingers are generally placed on thefinger grip adjacent the shield, while the thumb directs the plunger onthe pre-filled syringe. To move the shield, the free hand may be used toslide the shield, or the thumb and ring finger of the same hand may bemoved to the finger grip to hold the body. The index and middle fingersmay hold the sides of the shield and move it distally, thereby slidingthe shield until it is locked in the guarded position.

In a second preferred embodiment, the guard includes an attachablefinger grip plug and a plunger, in addition to the body and shield. Theplunger, with or without a thumb ring, a button plunger, or a “T” handleon one end, is attachable to the piston of a conventional unit dosecartridge. The finger grip plug may include a finger grip thereon, suchas a pair of wings or an octagonal flange. The finger grip plug and theproximal end of the body include cooperating members for locking thefinger grip section to the body and preventing the cartridge within thebody from moving substantially axially. Preferably, the finger grip plughas locking detents thereon, and the proximal end of the body includesan annular-shaped collar having tapered pockets therein adapted toreceive the locking detents.

The body and shield are generally provided pre-assembled in theunguarded position, as previously described, with the finger grip plugand plunger furnished separately. A cartridge, preferably a unit doseglass cartridge having a needle and needle cover on its distal end and apiston in its proximal end, is inserted into the proximal end of thebody until it is fully encapsulated within the cavity. Once fullyinserted, the finger grip plug is attached to the body, by aligning thelocking detents on the finger grip section with the tapered pockets inthe collar. The locking detents are inserted into the pockets until theyengage, substantially permanently and/or releasably enclosing the cavityand encapsulating the cartridge therein. In addition, the detents on thefinger grip plug may substantially engage the proximal end of thecartridge, thereby preventing the needle on the cartridge fromwithdrawing proximally into the body during use.

In addition, the plunger may include a radially extending detent or tabthat is compressed when the plunger is directed into the finger gripplug. The tab resiliently returns to its extended position once theplunger is fully inserted into the finger grip plug, thereby preventingthe plunger from being removed therefrom.

Once the guard, cartridge and-finger grip plug are assembled, the needleand needle cap on the cartridge extend through the distal ends of theshield and body. The plunger is attached to the piston in the cartridge,such as by a threaded bore on the distal end of the plunger which isadapted to screw into a threaded nipple on the piston. The device isthen ready to be used to deliver medication to a patient. Aftermedication is dispensed, the shield is slid into the guarded position,as with the first embodiment, with one or two hands.

In additional preferred embodiments, the syringe guard includes a bodyand a sliding shield similar to that described above, for holding a unitdose pre-filled syringe having its own plunger. In particular, the guardincludes a mechanism on the proximal end of the body, preferably on orwithin the finger grip, for substantially permanently (or releasablyunder certain conditions) securing the syringe within the guard andsubstantially preventing distal and/or proximal movement of the syringereceived therein. More preferably, the locking mechanism requires thesyringe to be inserted into the guard in a predetermined orientation,thereby facilitating viewing of a label or the like on the cartridgethrough the windows in the guard.

For example, the mechanism may include a clip or ring for clasping thefinger grip and the proximal flange of the syringe together. Preferably,a pair of clips are provided which slide over and engage the distal andproximal surfaces respectively of the finger grip and the flange of thesyringe.

Alternatively, the body may include an annular member within the openend thereof for creating an interference fit with the barrel of thesyringe inserted into the guard. Preferably, an annular ring extendsradially into the cavity, thereby frictionally engaging an enlargedproximal end of the syringe directed into the cavity to prevent removalof the syringe.

In a further alternative, the finger grip has a substantiallyrectangular shape including a recess in the proximal end for receivingthe flange or the proximal end of the pre-filled syringe. One or moretabs or detents extend into the recess from one or more walls of thefinger grip for engaging the flange of the syringe to secure it withinthe guard.

Alternatively, the finger grip may include a latch or cover forenclosing the recess once a syringe is inserted therein, the latchpreferably being attached to the finger grip by a hinge along a walldefining the recess. Once the flange of the syringe is directed into therecess, the latch is closed, preferably engaging a tab within the recessto prevent the latch from coming loose and releasing the syringe. Thelatch also preferably includes an aperture for accommodating a plungerof the syringe received within the body.

In a final preferred embodiment, the syringe guard is adapted to receiverelatively small cartridges or pre-filled syringes, for example a 0.5 mLunit dose pre-filled syringe including a rigid nose shield or needle caphaving a diameter larger than the barrel of the syringe. The guardincludes a body having a mechanism in its proximal end for lockablyengaging the proximal end of the pre-filled syringe received therein,such as those described above. In addition, the body includes one ormore semi-rigid members, for example pairs of tabs or longitudinal ribs,extending along the cavity for engaging the barrel of the syringe. Thebody may also include one or more lead-in ribs at or near the proximalend of the cavity for guiding the pre-filled syringe during insertion.When the syringe is inserted into the body, the cap engages the tabs asit enters the cavity. The tabs are forced radially out to allow the capto pass through the cavity. Once the cap extends beyond the proximal endof the body, the tabs resiliently return to abut or engage the wall ofthe barrel, thereby preventing substantial lateral movement of thesyringe within the body during use. The tabs also preferably prevent therails of the guard body from being compressed after use to preventinadvertent release of the cooperating locking detents on the shield andbody.

As will be understood, the present invention provides an improved guardfor medical cartridges or pre-filled syringes that may include as few astwo parts, but generally has no more than four parts. The device may beused for a wide variety of conventional prepackaged medications ordrugs, such as anesthesia, anti-thrombotic drugs, biological drugs orvaccines, for use within the medical and/or dental fields, where thecartridge or pre-filled syringe is generally disposed of after a singleuse. Because the device is relatively simple, the parts may be providedin standard configurations. For example, a single shield design may beprovided that fits on a variety of bodies for receiving cartridges orpre-filled syringes made by different manufacturers. In addition, thedistal openings in the body and/or the shield may be provided in aplurality of sizes to accommodate a variety of needle caps, lueradapters and the like. Thus, the guard may be more easily mass produced,reducing manufacturing costs, and thereby providing a more competitivelypriced disposable syringe guard.

In addition, the rectangular configuration of the present deviceprovides improved rigidity, thereby affording greater protection to thecartridge held in the guard. Although the cartridge or pre-filledsyringe is fully encapsulated within the guard, the windows in the guardallow the medical or dental professional to effectively monitor thecartridge or pre-filled syringe and the medication being delivered.

Finally, the slidable shield and cooperating detents allow the user tooperate the guard using only one hand, thereby allowing their other handto be free to perform other necessary tasks, such as restraining a youngpatient or providing improved access to the target region for theneedle. Once the shield is locked in the guarded position, the devicemay be disposed of safely if used properly, substantially eliminatingconcerns that the needle may become exposed and cause an accidentalstick.

Accordingly, it is a principal object of the present invention toprovide an improved unit dose syringe device that is easy to manufactureand convenient to use.

It is also an object to provide an improved syringe guard that affordsimproved protection for a cartridge or pre-filled syringe encapsulatedtherein but still allows effective monitoring of the medication beingdispensed.

Other objects and features of the present invention will become apparentfrom consideration of the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how it may becarried into effect, reference will be made, by way of example, to theaccompanying drawings, in which:

FIG. 1 is a perspective view of a first preferred embodiment of thesyringe guard of the present invention, holding a pre-filled syringe.

FIGS. 2A, 2B and 2C are perspective views of the body of the syringeguard of FIG. 1.

FIGS. 3A and 3B are perspective views of the shield of the syringe guardof FIG. 1.

FIG. 4 is a perspective view of the pre-assembled syringe guard about toreceive a conventional pre-filled syringe therein.

FIGS. 5A and 5B are perspective views of the syringe guard holding apre-filled syringe, with the shield in an unguarded position, and readyto be used to deliver medication to a patient.

FIGS. 6A and 6B are perspective views of the syringe guard holding apre-filled syringe, with the shield locked in a guarded position aftermedication has been dispensed from the syringe.

FIG. 7 is a perspective view of another preferred embodiment of thesyringe guard holding a unit dose cartridge, with the shield in theunguarded position, and ready to be used to deliver medication to apatient.

FIGS. 8A, 8B, 8C and 8D are perspective views of the body of the syringeguard of FIG. 7.

FIGS. 9A and 9B are perspective views of the shield of the syringe guardof FIG. 7.

FIG. 10 is a perspective view of the finger grip plug and plunger of thesyringe guard of FIG. 7.

FIGS. 11A and 11B are perspective views of standard unit dosecartridges.

FIG. 12 is a perspective view of the syringe guard with a unit dosecartridge partially inserted into the body, and with the plungerassembly aligned and ready to be attached to the body.

FIG. 13 is a perspective view of the syringe guard holding a cartridge,with the shield locked in the guarded position after medication has beendispensed from the cartridge.

FIG. 14A is a side view of a third preferred embodiment of a syringeguard holding a pre-filled syringe, with the shield in the guardedposition.

FIG. 14B is a perspective view of the syringe guard of FIG. 14A.

FIG. 14C is a top view of the syringe guard of FIG. 14A.

FIG. 15A is a perspective view of a fourth preferred embodiment of asyringe guard holding a pre-filled syringe, with the shield in theguarded position.

FIG. 15B is a cross-section of the syringe guard of FIG. 15A taken alongline B-B.

FIG. 15C is a top view of the syringe guard of FIG. 15A.

FIG. 15D is a detail of the cross-section of FIG. 15B.

FIG. 16A is a perspective view of a fifth preferred embodiment of asyringe guard holding a pre-filled syringe, with the shield in theguarded position.

FIG. 16B is a detail of the syringe guard of FIG. 16A, showing thedetents retaining the syringe in the syringe guard.

FIG. 16C is a detail of an alternate embodiment of the detents shown inFIG. 16B.

FIG. 16D is a detail of another alternate embodiment of the detentsshown in FIG. 16B.

FIG. 17A is a perspective view of a sixth preferred embodiment of asyringe guard holding a pre-filled syringe, with the shield in theguarded position.

FIG. 17B is a perspective view of the syringe guard of FIG. 17A.

FIG. 17C is a cross-section of the syringe guard of FIG. 17A taken alongline C-C.

FIG. 17D is a cross-section of the syringe guard of FIG. 17B taken alongline D-D.

FIG. 18A is a perspective view of a body for a seventh preferredembodiment of a syringe guard for receiving a relatively smallpre-filled syringe.

FIG. 18B is another perspective view of the syringe guard body of FIG.18A.

FIG. 18C is a side view of a preferred embodiment of a syringe guardincluding the body of FIG. 18A, holding a unit dose syringe.

FIG. 18D is a side view of the syringe guard of FIG. 18C, with theshield in the guarded position.

FIG. 19 is a perspective view of an alternative embodiment of thesyringe guard body of FIG. 18A.

FIG. 20 is a perspective view of another alternative embodiment of thesyringe guard body of FIG. 18A.

FIG. 21A is a side view of an alternative embodiment of the syringeguard body of FIG. 8A for receiving relatively short unit dose ampules.

FIG. 21B is a perspective view of the syringe guard body of FIG. 21A,holding a short unit dose cartridge therein.

FIG. 21C is a detail of the syringe guard of FIG. 21A.

FIG. 22 is a perspective view of an alternative embodiment of thesyringe guard of FIG. 7.

FIG. 23 is a cross-sectional detail of the syringe guard of FIG. 22,taken along line 23-23.

DETAILED DESCRIPTION OF THE INVENTION

Turning to the drawings, FIG. 1 shows a first preferred embodiment ofthe present invention, namely a syringe guard 10 for holding apre-filled unit dose syringe 90. Generally, the guard 10 comprisestwo-parts, namely a housing or body 20 for receiving and holding thepre-filled syringe 90, and a protective case or shield 60 slidablyattached to the body 20. Both the body 20 and the shield 60 aregenerally molded from plastic, such as polypropylene, K-Resin®)(synthetic resinous polymers of butadiene and styrene), orpolycarbonate, and are preferably clear and substantially colorless tofacilitate observation of the pre-filled syringe received therein.Alternatively they may be translucent or opaque, and may be colored,such as a latex color, or a flesh tone, such as off-white, brown, orblack.

Turning to FIGS. 2A, 2B and 2C, the body 20 is an elongate member,preferably having a substantially rectangular cross-section, comprisingtwo side rails 28, an open proximal end 22, and an open distal end 24.The rectangular shape is preferred as it provides superior rigidity,protecting the syringe therein from lateral forces that might otherwisedamage it, particularly if the syringe is made of glass. Alternativelyinstead of the rectangular cross-section, the body and shield may havecorresponding oval or round cross-sections providing sufficient rigidityto protect the cartridge received therein.

In addition, the body 20 has a substantially rigid collar 32 on thedistal end 24, and a finger grip 50 on the proximal end 22, bothattached to or preferably integrally molded onto the body 20.Alternatively, instead of comprising side rails 28, the body 20 maycomprise a substantially rectangular body having four side walls (notshown).

The two side rails 28 generally have a “C” shape and define a cavity 26in the body 20, the cavity 26 extending axially from the proximal end 22to the distal end 24 of the body 20. The inside surface 30 of the rails28 is preferably concave, conforming substantially to the outer diameterof a standard unit dose pre-filled syringe. Alternatively, if the siderails 28 have a flat or “C” channel inside surface 30, guide rails (notshown) or the like may be provided on the inside surface 30 to directthe pre-filled syringe 90 (FIG. 4) into the cavity 26 and hold it,thereby substantially preventing lateral movement which may damage thepre-filled syringe 90.

As shown in FIGS. 2A and 2C, the finger grip 50 generally comprises apair of wing-like members 52 molded onto the proximal end 22 of the body20, thereby generally defining a “T” shape. Each wing-like member 52includes a distal surface or finger ledge 54, and an outer grippingsurface 56 extending proximally from the outer edge 54a of the fingerledge 54. The outer gripping surface 56 may include a lip, grooves orother irregularities (not shown) protruding radially from its proximalend or set in the surface 56, if desired to improve the hold on thefinger grip 50. Lateral surfaces 55 extend proximally from the fingerledges 54 between the gripping surfaces 56, thereby defining a recess oropen proximal end 51 communicating with the cavity 26 in the body 20.The lateral surfaces 55 of the finger grip 50 include a plurality oflocking detents 58 partially defining an aperture or slot 57 for holdingthe pre-filled syringe (not shown in FIGS. 2A and 2B) inserted into thecavity 26, as will be described further below.

Turning to FIG. 2B, the collar 32 extending from the distal end 24preferably has a substantially annular shape, including an opening 34extending therethrough adapted to allow the needle and needle cover onthe pre-filled syringe (not shown) in the cavity 26 to extend beyond thebody 20. The opening 34 preferably has a diameter smaller than thecavity 26, such that the distal end 24 substantially retains thepre-filled syringe inside the cavity 26, preventing distal movement.Alternatively, the distal end 24 may be tapered or otherwise partiallyobstructed, as long as it engages the distal end of the pre-filledsyringe, preventing distal movement of the pre-filled syringe, and doesnot substantially interfere with the needle and cover extending beyondthe distal end 24.

The distal end 24 may include an expandable “collet” (not shown) definedby a plurality of longitudinal slots extending proximally a shortdistance from the distal end 24. The collet may have a diameter smallerthan that of the syringe barrel, hub or needle cap as desired, therebyallowing the distal end 24 to be resiliently expanded to substantiallyengage the syringe received therein. In a further alternative, theopening 34 in the distal end 24 may have a sufficiently large diameterto freely allow the distal end of the pre-filled syringe to extendtherethrough, the pre-filled syringe being locked substantially withinthe body exclusively by a locking mechanism on the proximal end 22 orfinger grip 50 of the body 20, as described more particularly below, andnot by a collar on the distal end 24.

The side rails 28 define two elongate openings or windows 36 extendinglongitudinally between the finger grip 50 and the distal end 24,allowing observation of the pre-filled syringe held in the body 20.Alternatively, if a four-walled body is provided, an elongate opening orwindow may be integrally formed in one or more of the side walls,preferably in two walls on opposite sides of the body 20. The body 20also includes one or more stop tabs 38 attached or molded directly tothe body 20. Preferably, stop tabs 38 are molded onto the body 20 on twoopposite sides of the distal end 24 of the body 20.

The body 20 also includes one or more sets of detent pockets, preferablyhaving a set of proximal detent pockets 40 adjacent the finger grip 50,and a set of distal detent pockets 42 at a more distal location on thebody 20. The detent pockets lock the relative movement between theshield 60 and body 20, as is explained more fully below.

Turning now to FIGS. 3A and 3B, the protective case or shield 60 is atubular member adapted to slidably fit on the body 20, preferably havinga substantially rectangular interior shape which conforms to the shapeof the body 20. The shield 60 includes four side walls 61 a, 61 b, anopen proximal end 62, and an open distal end 63. The shield 60 has apair of detent arms 70 and a plurality of detents 71 attached to orpreferably integrally molded directly into the side walls 61 b. Assemblytabs 72 with sloping or ramped interior surfaces 73 are molded into andextend proximally from the side walls 61 a.

The detents 71 preferably have shapes corresponding substantially to theshapes of the detent pockets 40, 42 in the body 20. The proximal edges71 b are blunt or preferably oblique to engage the proximal surfaces 40b or 42 b as described below and to maximize bearing surface area,particularly to stabilize a shorter guard 10. In addition, the detentarms 70 may include indents 170 for controlling the flexural strength ofthe detent arms 70 as the arms 70 vary in size and thickness inembodiments adapted to accommodate a variety of syringes.

At least one wall 61 a, preferably the two opposite walls 61 a, includesan elongate opening or window 64 therethrough. The window 64 allowsobservation of the pre-filled syringe received in the body 20, and alsoprovides a traveling slot for the stop tab 38 on the body 20. The window64 has a proximal edge 66 and a distal edge 68 defined by the wall 61 awhich limit the relative movement of the shield 60 to the body 20, aswill be explained more fully below. Alternatively, the window 64 may bedivided by a cross-member (not shown) molded into the wall 61 a whichextends transversely across the window 64 if it is desired to furtherlimit the movement of the shield 60.

Optionally, the side walls 61 a, 61 b may include wings, a ring orsimilar finger holds (not shown) extending radially from the shield 60to ease movement of the shield 60 in relation to the body 20. Inaddition, the side walls 61 a, 61 b may provide a flat surface ontowhich a label may be applied, for example to identify the drug or otherfluid contained within the pre-filled syringe 90 received within theguard 10, or an embossed pattern may be molded, possibly including aname or a logo.

Turning to FIG. 4, the guard 10 is normally provided with the-body 20and shield 60 pre-assembled as shown. To assemble the guard 10, thedistal end 24 of the body 20 (see FIG. 2A) is inserted into the openproximal end 62 (see FIG. 3A) of the shield 60, with the window 36 inthe body 20 aligned with the side wall 61 a of the shield 60 having thewindow 64 therein. As the body 20 is inserted, the stop tab 38 (the stoptab and window not shown on the opposite side operate substantially thesame way) engages the tapered interior edge 73 of the assembly tab 72 onthe shield 60 (see FIG. 3B), allowing the stop tab 38 to pass under thewall 61 a. After the stop tab 38 passes under the wall 61 a, it thenenters the window 64 where it may freely travel.

Together, the stop tab 38 and window 64 allow the shield 60 to slidablymove in relation to the body 20, but substantially define the limits ofthat relative movement. The shield 60 may slide proximally and distallyuntil the stop tab 38 abuts a distal edge 68 and a proximal edge 66,respectively, of the window 64. Specifically, when the stop tab 38engages the distal edge 68 of the window 64, as shown in FIG. 4, theshield 60 is in a proximal or unguarded position. When the stop tab 38engages the proximal edge 66 of the window 64, as shown in FIGS. 6A and6B, the shield is in a distal or guarded position.

Referring to FIGS. 5A and 5B, when the stop tab 38 abuts the distal edge68 of the window 64, the cooperating detents 71 and proximal detentpockets 40 operate to hold the shield 60 in the unguarded position. Thesloping distal edges 71 a of the detents 71 engage the sloping distaledges 40 a of the proximal detent pockets 40 on the body 20, therebypreventing the shield 60 from moving distally.

Turning again to FIG. 4, once assembled, the guard 10 is ready toreceive a cartridge, such as a conventional unit dose pre-filled syringe90. Although the pre-filled syringe 90 shown in FIGS. 1 and 4 is thepreferred delivery system for use with the syringe guard of the presentinvention, it will be appreciated that the syringe guard may be used forother pre-filled or unit dose delivery systems, and that the termcartridge includes other such known systems. The pre-filled syringe 90generally has a substantially smooth-walled cylindrical barrel 92, adistal end or hub 94 including a hypodermic needle 95, a needle cover orcap (not shown), an enlarged proximal end 93 having a flange 96, and aplunger 98. The flange 96 generally includes a flat edge 96a in apredetermined orientation with a label or graduation marks 92 a on thebarrel 92 of the pre-filled syringe 90. Preferably, the flange 96includes two opposite flat edges 96 a extending between two curved edges96 b, thereby defining a generally rectangular-shaped finger grip 96.The flange 96 may have a sufficiently large width to provide a fingergrip for the pre-filled syringe 90, or may simply be a small lip tofacilitate manufacturing, for example on a filling line.

The distal end 94 of the pre-filled syringe 90 is inserted into therecess 51 of the finger grip 50 and the open proximal end 22 of the body20. The pre-filled syringe 90 enters the cavity 26 and progressesdistally until the distal end 94 of the pre-filled syringe 90 becomescoextensive with and/or directly engages the distal end 24 of the body20. The distal end 94 of the pre-filled syringe 90 may simply abut thedistal end 24 of the body 20, or alternatively the distal end 94 maypartially enter the opening 34 and engage the collar 32, therebyproviding additional protection from lateral movement of the pre-filledsyringe 90 (FIGS. 1 and 6A).

As the pre-filled syringe 90 becomes fully encapsulated within thecavity 26, the flange 96 on the proximal end 93 of the pre-filledsyringe 90 contacts the locking detents 58 on the finger grip 50. Thelocking detents 58 have tapered proximal edges 58 a, allowing thepre-filled syringe 90 to be directed further distally, the flange 96moving the locking detents 58 aside and entering the slot 57. As isshown in FIGS. 5A and 5B, the locking detents have blunt distal edges 58b which prevent the syringe 90 from being removed proximally from theslot 57, thereby substantially permanently locking the pre-filledsyringe 90 into the body 20, an important feature of the presentinvention. Thus, the slots 57 preferably substantially permanently lockthe proximal end 93 of the pre-filled syringe 90 within the finger grip50, thereby preventing axial (i.e. proximal and/or distal) movement ofthe syringe 90 within the guard 10.

Although the pre-filled syringe 90 is considered substantiallypermanently encapsulated within the guard 10, the material of the fingergrip 50 may have sufficient flexibility to allow a tool (not shown) tomove the detents 58 to allow the pre-filled syringe 90 to be removedfrom the body 20. Preferably, the tool applies a distal force to each ofthe proximal edges 56a of the outer surface 56, causing the lateralsurfaces 55 and detents 58 to expand outward to release the flange 96.Alternatively, the tool may engage the lateral surfaces 55 directly andforce them outward to release the flange 96 from the slots 57.

Thus, if an incorrect pre-filled syringe 90 is inserted into the guard10 during factory assembly, it may be released from the guard 10 withoutdamaging the guard 10 and/or the pre-filled syringe 90, thereby allowingboth to be reused. This may be particularly important for pre-filledglass syringes for which the flange 96 is often structurally the weakestpoint of the pre-filled syringe 90. Thus, a pre-filled glass syringe 90may be releasably encapsulated within the guard 10, allowing removal ofthe syringe 90 under certain controlled conditions. The finger grip 50,however, is sufficiently rigid that, during normal use for example by amedical professional, the pre-filled syringe 90 will not be removablefrom the guard 10.

In addition, the generally rectangular-shaped flange 96 may establish apreferred orientation for the pre-filled syringe 90 to be received inthe guard 10. Preferably, the shape of the flange 96 allows thepre-filled syringe 90 to be received within the slots 57 only in anorientation that allows the label 92 a to be visible through the window64 of the guard 10 during use (see FIG. 5A). For example, the detents 58may engage the opposing flat edges 96 a of the flange 96 (not shown),thereby preventing the pre-filled syringe 90 from being rotated axiallywithin the body 26. Alternatively, the finger grip 50 the body 20 may beprovided with any symmetrical or predetermined shape adapted tocorrespond substantially to the shape of the flange 96 on a cartridge orpre-filled syringe 90 being received therein, thereby encapsulating thecartridge within the body in a predetermined orientation about thelongitudinal axis of the cartridge. For example, an elliptical or ovalfinger grip (not shown) may provide an appropriate alternative shape, ora round finger grip (not shown) may be provided if it has a recesshaving a shape corresponding to that of the flange 96 on the pre-filledsyringe 90.

Referring to FIGS. 1 and 5A, once the pre-filled syringe 90 is lockedinto the guard 10, the needle 95 and its cover (not shown) extendthrough the opening 34 on the collar 32 and the opening 65 on the distalend 63 of the shield 60. The distal end 63 of the shield 60 has agenerally tapered configuration defining an opening 65 through which theneedle.95 may extend. Preferably, the length of the shield 60 issubstantially coextensive with the barrel 92 of the pre-filled syringe90, allowing the full length of the needle 95 to extend beyond thedistal end 63 of the shield 60, but protecting the hub 94 of thepre-filled syringe 90.

The opening 65 is generally circular and has a diameter larger than thatof the syringe barrel 92 and/or hub 94, and may be provided with avariety of diameters or configurations to facilitate use of thepre-filled syringe 90.. For example, the diameter of the opening 65 maybe sufficiently large to allow a luer adapter (not shown) or otheralternative distal tip to be provided on the pre-filled syringe 90 or tobe attached to the hub 94 during use. Most preferably, however, theopening 65 has a diameter sufficiently small to minimize the risk ofaccidental sticks, for example to prevent a finger from being directedinto the shield 60 after use.

The pre-filled syringe 90 encapsulated within the guard 10 may then beused in a conventional manner to deliver the medication in the barrel92. The medical professional typically holds the pre-filled syringe byplacing his or her index finger on a finger ledge 54, his or her middlefinger on the other finger ledge 54, and his or her thumb on the end 99of the plunger 98. The cover (not shown) is removed, the needle 95 isinserted into the patient, and the medication is delivered by directingthe plunger 98 distally with the thumb. As can be seen from FIGS. 1 and5A, the windows 64 and 36 provide constant observation of the barrel 92of the pre-filled syringe 90, allowing the user to closely monitordelivery of the medication. The finger grip 50 also preferably has asufficiently large size relative to the flange 96 to provide improvedmanipulation by the user as compared to using the pre-filled syringe 90alone.

After the medication is dispensed, the needle 95 is withdrawn from thepatient, and the self-shielding feature of the guard 10 is engaged. Theuser holds the body 20, typically by placing his ring finger on thegripping surface 56 adjacent his middle finger, and moving his thumbfrom the plunger 98 to the other gripping surface 56. The index andmiddle fingers, already adjacent the side walls 61 b of the shield 60,grip the walls 61 b and are moved distally, thereby sliding the shield60 distally until it reaches the guarded position, shown in FIG. 6A.Alternatively, while one hand holds the finger grip 50, the shield 60may be directed to the guarded position with the free hand of the user.

Because the cooperating detents 71 and detent pockets 40 hold the shield60 in the unguarded position, force must be applied to move the shield60 distally. As previously discussed, the detents 71 have sloping distaledges 71 a and blunt or oblique proximal edges 71 b (FIG. 3B), andsimilarly, the proximal detent pockets 40 have sloping distal edges 40 aand blunt or oblique proximal edges 40 b (FIG. 5B). Because of thesloping distal edges 71 a, 40 a, the engagement between the detents 70and the proximal detent pockets 40 may be overcome by pushing the shield60 distally in relation to the body 20. The detent arms 70 move radiallyoutward as the detents 71 move distally up the sloping edges 40 a untilthe detents 71 leave the detent pockets 40. The shield may then be movedfreely, the stop tab 38 traveling along the window 64, until the stoptab 38 abuts the proximal edge 66 of the window 64, reaching the guardedposition.

As shown in FIG. 6A, because of the predetermined location of the distaldetent pockets 42, when the stop tab 38 reaches the proximal edge 66 ofthe window 64, the detents 71 substantially simultaneously enter thedistal detent pockets 42. The blunt or oblique proximal edges 71 b ofthe detents engage the similarly shaped proximal edges 42 b of thedistal detent pockets 42, thereby preventing the shield 60 from beingmoved proximally. The corresponding shape of the engaged proximal edges71 b, 42 b may also maximize bearing surface to prevent misalignment ofthe shield 60. Furthermore, because the stop tab 38 abuts the proximaledge 66 of the window 64, the shield 60 may not be moved furtherdistally. Thus, the shield 60 is thereby substantially permanentlylocked in the guarded position.

As can be seen from FIG. 6A, when the shield 60 is moved distally intothe guarded position, the distal end 63 of the shield 60 passes over theneedle 95, covering the needle 95. Once the shield 60 is locked in theguarded position, the needle 95 is no longer accessible, therebysubstantially eliminating the risk of accidental sticks, and preventingreuse of the syringe 90. The guard 10 and pre-filled syringe 90 may thenbe disposed of safely.

Turning now to FIGS. 7-13, and 22-23, a second preferred embodiment isshown, namely a syringe guard 10 for holding a unit dose cartridgemanufactured without its own plunger, such as the unit dose glasscartridges 190 made by Carpuject and Tubex (see FIGS. 11A and 11B).Generally, the guard 10 comprises four parts, namely a housing or body20 for receiving and holding the cartridge 190, a protective case orshield 60 slidably attached to the body 20, a finger grip plug 130, anda plunger 120. As before, the parts are molded from plastic, such aspolypropylene, K-Resin® (synthetic resinous polymers of butadiene andstyrene), or polycarbonate, having a clear, colorless finish.

Turning to FIG. 8A, the body 20 has two elongate side rails 28, aproximal end 22 and a distal end 24. As shown in FIG. 8B, a collar 32 ismolded directly on the distal end 24 and has an opening 34 therethrough.Alternatively, as in FIG. 8C, it may be appropriate to provide thedistal end 24 with the opening 34 formed directly through it andeliminate the collar 32.

The two side rails 28 have concave inside surfaces 30 conformingsubstantially to the outer diameter of a standard unit dose cartridge(not shown in FIG. 8A), thereby defining a cavity 26 in the body 20 forholding the cartridge. The outer edges of the side rails 28 define asubstantially rectangular cross-section for the body 20, providing asubstantially rigid structure for protecting the cartridge encapsulatedwithin the body 20. In addition, the side rails 28 define two elongateopenings or windows 36 extending between the proximal end 22 and thedistal end 24, thereby allowing observation of the cartridge. The body20 also includes one or more stop tabs 38 molded onto the body 20,preferably on two opposite sides of the distal end 24. Similar to theprevious embodiment, the body 20 also includes a set of proximal detentpockets 40 adjacent the finger grip collar 110 (or ring 112), and a setof distal detent pockets 42 at a more distal location on the body 20.

Turning to FIG. 8D, the proximal end 22 of the body 20 includes a fingergrip collar 110, preferably molded directly thereon. The finger gripcollar 110 has a circular opening 111 extending through it,communicating with the cavity 26 in the body 20. Tapered grooves 114 areformed on the inside the finger grip collar 110, defining taperedpockets 118 used to attach the finger grip plug 130 to the body 20.Notches 116 are formed in the finger grip collar 110 adjacent thetapered grooves 114 to provide easy orientation during attachment. Thefinger grip collar 110 also includes a finger grip ring 112 whichextends radially out from the distal end of the finger grip collar 110,allowing the body 20 to be held more easily.

Turning now to FIGS. 9A and 9B, the protective case or shield 60 is atubular member adapted to slidably fit on the body 20, similar to theshield previously described. The shield 60 includes four side walls 61a, 61 b, an open proximal end 62, and an open distal end 63. The shield60 has a pair of detent arms 70 and detents 71 molded into the sidewalls 61 b. Assembly tabs 72 with tapered interior surfaces 73 aremolded into and extend proximally from side walls 61 a. Finger holds 76are molded onto and extend radially from the side walls 61 a.

The two opposite walls 61 a each include elongate windows 64 a, 64 bwhich allow observation of the cartridge in the body 20. The distalwindow 64 a also provides a traveling slot for the stop tab 38 on thebody 20. Each window 64 a has a proximal edge 66 defined by across-member 164 and a distal edge 68 defined by the wall 61 a. Thewindows 64 a and the stop tabs 38 together limit the relative movementof the body 20 and the shield 60, as previously described.

Referring now to FIGS. 10, 22, and 23, the plunger 122, preferablyhaving a cruciform cross-section, has a thumb ring 128 on its proximalend 124 (FIG. 10), and a threaded bore 127 on its distal end 126. Thethreaded bore 127 is a shallow hole having a standard thread pattern,adapted to screw onto the threaded nipple 194 on the piston 193 on aconventional medical cartridge 190 (FIG. 23). Alternative distal ends126 may be provided, such as a harpoon, a threaded nipple, an adhesivematerial, molded ribs, a frictional surface or the like (not shown), ifappropriate for attaching to the piston of a desired medical cartridge.In addition, alternative proximal ends may be provided, such as a buttonend 248 (FIG. 22), or a “T” type thumb grip (not shown), instead of thethumb ring 128.

In addition, the plunger 120 may also include a one-way locking memberthat allows the plunger 120 to be substantially permanently insertedinto the finger grip plug 130. Preferably, as shown in FIG. 23, thelocking member includes a semi-rigid tongue or tab 220 formed adjacentthe distal end 126 of the plunger shaft 122. The tab 220 extendsproximally and radially out from the plunger shaft 122, but may becompressed against the shaft 122 to facilitate insertion distally intothe finger grip plug 130. Once inserted, the tab 220 resiliently returnsto its extended position to prevent withdrawal of the plunger 130 fromthe finger grip section 130, as described more particularly below.

Returning to FIG. 10, the finger grip plug 130 comprises a central hub134, a pair of finger ledges 132 extending radially from the hub 134,and a pair of fingers or legs 138 extending distally from the hub 134.Alternatively, instead of the pair of finger ledges or wings 134, thefinger grip plug 130 may include a substantially symmetrical grip, suchas an octagonal finger grip 135 as are often used on dental syringes(FIG. 22). The hub 134 also has a passage extending axially through it,adapted to receive the plunger 120. The fingers 138 include lockingdetents 139, which are described more fully below.

Turning to FIG. 12, the guard 10 is normally provided with the body 20and shield 60 pre-assembled and the plunger 120 and finger grip plug 130loose. To pre-assemble the body 20 and shield 60, the distal end 24 ofthe body 20 (see FIG. 8A) is inserted into the proximal end 62 of theshield 60 (see FIG. 9A), with the window 36 in the body 20 aligned withthe wall 61 a of the shield 60 having the windows 64 a, 64 b therein.The stop tab 38 includes a sloped or ramped distal edge 38 a thatengages the tapered interior edge 73 of the assembly tab 72 (see FIG.9B), allowing the stop tab 38 to pass under the wall 61 a until itenters the proximal window 64 b. The ramped distal edge 38 a also allowsthe stop tab 38 to pass under the cross-member 136, until it enters andtravels freely in the distal window 64 a. The detent arms 70 aredirected radially outward to prevent them from engaging the distaldetent pockets 42, and then the shield 60 is directed proximally untilthe detents 71 engage the proximal detent pockets 40, holding the shield60 in the unguarded position.

The pre-assembled body 20 and shield 60 are then ready to receive acartridge, such as the conventional unit dose glass cartridges 190 a and190 b shown in FIGS. 11A and 11B respectively, although alternatively,the device may be used to hold other vials, or ampules. The cartridges190 generally comprise a barrel 92, a distal end or hub 94 including ahypodermic needle 95, a needle cover or cap (not shown), and a proximalend 93 having a threaded piston therein 193 (see FIG. 23).

Turning again to FIG. 12, the distal end 94 of the cartridge 190 isinserted into the open proximal end 22 of the body 20. The cartridge 190enters the cavity 26 and progresses distally until the distal end 94 ofthe cartridge 190 extends through or engages the distal end 24 of thebody 20. Because different types of distal ends are provided ondifferent cartridges, the distal point of engagement between the body 20and the cartridge 190 may vary. For example, a standard Carpujectcartridge 190 a, shown in FIG. 11A, requires the body 20 to have adistal end 24 similar to that shown in FIG. 8C, such that the distalribs 94 a on the cartridge 190 a enter the opening 34 in the distal end24 of the body 20. In contrast, a standard Tubex cartridge 190 b, shownin FIG. 11B, requires a distal end 24 on the body 20 such as the collar32 shown in FIG. 8B, thereby allowing the edge 94b on the cartridge 190b to engage the collar 32.

Turning to FIGS. 12 and 13, once the cartridge 190 is fully insertedinto the cavity 26, the finger grip plug 130 is attached to the body 20.The fingers 138 on the finger grip plug 130 are aligned with the notches116 in the finger grip collar 110 on the body 20. The fingers 138 areinserted into the notches 116, compressing the fingers radially as theyenter the tapered pockets 118 (FIG. 8D) and pass through the collar 110.Upon reaching the windows 36, the fingers 138 expand radially outwardagain. The locking detents 139 have blunt proximal edges 139 a whichengage the distal side 112 b of the finger ring 112, therebysubstantially permanently locking the finger grip plug 130 to the body20.

Preferably, when the finger grip plug 130 is locked onto the body 20,the cartridge 190 is simultaneously encapsulated within the cavity 26(FIG. 23). The body 20 generally has a length correspondingsubstantially to that of the cartridge 190. When the finger grip plug130 is locked onto the body 20, the distal ends 139 b of the fingers 138then preferably engage the proximal end 93 of the cartridge 190,substantially preventing proximal movement of the cartridge 190.

In addition, the body 20 may be used to encapsulate a cartridge 190 thatis substantially shorter than the length of the body 20 but has asimilar diameter to that of the cavity 26. As shown in FIGS. 21A-21C,the distal end 24 may include one or more tabs 240 formed thereon forsecuring a cartridge, such as the standard Tubex cartridge 190 b (seeFIG. 11B), within the body 20. Preferably, a pair of semi-rigid tabs 240are provided on the distal end 24 of the body 20 extending partiallyinto the opening 34, each tab 240 having a generally ramped innersurface 240 a and a substantially blunt distal surface 240 b. The innersurface 240 a preferably defines a diameter smaller than that of the hub94 of the cartridge 190, while the diameter of the opening 34 is smallerthan that of the barrel 92.

The tabs 240 are ramped distally inward, thereby allowing the hub 94 tobe directed distally past the tabs 240, forcing the tabs 240 slightlyoutward. Once the hub 94 extends beyond the tabs 240, the tabs 240resiliently snap back inward, the blunt distal edge 240 b engaging theblunt proximal edge 94 a of the hub 94. Thus, the opening 34substantially prevents distal movement of the cartridge 190, while thetabs 240 prevent proximal movement.

Alternatively, the cavity 26 may include one or more tabs, annularridges or similar retaining detents (not shown) at predeterminedlocations in the body 20 corresponding to the length of one or moreshort cartridges. When the cartridge 190 is directed into the body 20,the smooth-walled barrel 92 passes freely over the tab or ridge,preferably facilitated by a ramped proximal edge thereof. When thecartridge 190 is fully inserted into the body 20, the needle 95 shouldextend beyond the distal end 24 and the proximal end 93 should beengaged by a blunt distal edge of the tab or ridge, thereby preventingthe cartridge 190 from withdrawing proximally into body 20 during use.

As shown in FIGS. 12, 13 and 23, with the cartridge 190 fully insertedinto the body 20, the plunger 120 is then attached to the piston 193 inthe cartridge 190, preferably by screwing the threaded bore 127 on theplunger 122 to a threaded nipple 194 on the piston 193. As describedabove, the plunger shaft 122 preferably includes a tab 220 forsubstantially permanently retaining the distal end 126 of the plunger120 within the finger grip plug 130. The finger grip plug 130 includes apassage 140 extending distally therethrough for receiving the plunger120. The passage 140 includes a lip 142, preferably extending radiallyabout the passage 140, for engaging the tab 220 to substantially retainthe plunger 120.

The tab 220 includes a ramped distal surface 220 b which allows it to beforced inward when the distal end 126 of the plunger 120 is directedinto the passage 140. Once the tab 220 passes distally beyond the lip142, it resiliently returns to its outward extended position. If theplunger 120 is drawn proximally, the blunt proximal edge 220 a abuts thelip 142, thereby preventing the plunger 120 from being pulled out of thefinger grip plug 130. In addition, the plunger shaft 122 may have across-section similar in size to the passage, preventing the fingers 138from being forced radially inward and thereby further securing thefinger grip plug 130 to the body 20 of the syringe guard 10.

Referring to FIG. 7, with the shield 60 in the unguarded position, theneedle 95 of the cartridge 190 extends through the opening 65 and beyondthe distal end 63 of the shield 60. The device is then ready to be usedto deliver the medication contained within the cartridge 190. Similar tothe procedure described above, the user places his index and middlefingers on the finger ledges 132, and his thumb in the ring 128. Theneedle cover (not shown) is removed, the needle 95 is inserted into thepatient, and the medication is dispensed by directing the plunger 122distally with the thumb. As shown in FIG. 7, the windows 64 and 36 allowconstant observation of the barrel 92 of the cartridge 190, allowing theuser to closely monitor delivery of the medication.

After the medication is dispensed, the needle 95 is withdrawn from thepatient, and the self-shielding feature of the guard 10 is engaged,similar to the procedure described previously. As the shield 60 is moveddistally, the detents 70 leave the proximal detent pockets 40. When theshield reaches the guarded position, the detents 71 enter the distaldetent pockets 42, locking the shield 60.

Turning now to FIGS. 14A-14C, a third preferred embodiment of a syringeguard 10 in accordance with the present invention is shown. The syringeguard 10 includes a body 20 and a shield 60 similar to that describedabove, for receiving a pre-filled syringe 90 including its own plunger(not shown).

The syringe guard 10 also includes a finger grip 150 and a detachableclip or ring 160 for securing the pre-filled syringe 90 to the proximalend 22 of the syringe guard 10. The finger grip 150 includes a pair ofwings 152 having a distal surface 154 and a proximal surface 156.Preferably, the wings 152 have a shape substantially similar to theflange 96 on the proximal end 93 of the syringe 90. The clip 160preferably includes a pair of similarly or identically shaped members,defining a “C” cross-section. The clip 160 includes a cavity 162 havinga shape for substantially engaging the finger grip 150 and the flange96, and includes an aperture 164 for accommodating the plunger (notshown) of the pre-filled syringe 90, the cavity 162 and aperture 164together defining a plurality of substantially rigid retaining fingers166.

During use, the pre-filled syringe 90 is introduced into the cavity 26within the body 20 until the distal edge 96 a of the flange 96 abuts theproximal surface 156 of the finger grip 150, and the needle 95 extendsbeyond the distal end 24 of the body 20. A clip 160 is then directedover the flange 96 and each finger grip wing 152, the retaining fingers166 substantially engaging the respective proximal and distal surfaces93 b, 154.

Thus, the clips 160 prevent the pre-filled syringe 90 from movingaxially (i.e. distally and/or proximally) within the guard 10. Inaddition, the clips 160 may be sufficiently rigid to prevent theproximal end 94 of the pre-filled syringe 90 from moving substantiallylaterally during use, thereby possibly eliminating the need for aretaining collar on the proximal end of the body 20. In addition, theapertures 164 on the clips 160 allow the plunger (not shown) to befreely directed distally and/or proximally to dispense medication asdesired without substantial interference by the clips 160. In addition,the clips 160 and/or the surfaces 93 a, 154 may include cooperating tabsand pockets (not shown) for locking the clips 160, although the clips160 may be sufficiently retained by friction and/or force fitting theminto place.

Alternatively, a detachable ring or clip (not shown) may be providedinstead of the pair of clips 160. The ring may be a single hinged piece,with a plurality of retaining fingers or having a recessed perimeter,that may be wrapped around the plunger to engage the finger grip 150 andthe flange 96.

Turning now to FIGS. 15A-15D, a fourth embodiment of a syringe guard 10is shown. Similar to the previous embodiments, the syringe guard 10includes a body 20 with a finger grip 250, and a shield 60. The fingergrip 250 includes an annular shaped collar 172 therein with an annularring 174 extending radially inward into the cavity 26. Alternatively,the annular collar may be located elsewhere within the body 20, forexample in a portion of the cavity 26 distal of the finger grip 250.

Preferably, the annular ring 174 defines a diameter slightly smallerthan the outer diameter of the proximal hub 192 of the syringe 90.Alternatively, the annular ring 174 may define a diameter slightlysmaller than the barrel 92 itself, or the ring may define anintermittent annular shape (not shown).

A pre-filled syringe 90 may be directed into the cavity 26, the proximalhub 192 engaging the annular ring 174. This creates an interference orfrictional fit between the annular ring 174 and the proximal hub 192,thereby substantially retaining the pre-filled syringe 90 within thebody 20.

In addition, the finger grip 250 preferably has a substantiallyrectangular shape corresponding to the generally rectangular shape ofthe flange 96 on the conventional unit dose pre-filled syringe 90. Thus,the flange 96 may be securely received within a recess 251 within thefinger grip 250, thereby preventing the pre-filled syringe 90 from beingrotated along its longitudinal axis when encapsulated within the body20, for example to facilitate observation of a label (not shown) on thebarrel-92 through the window 64.

Turning to FIGS. 16A-16D, a fifth preferred embodiment of a syringeguard 10 is shown, that has a body 20, a finger grip 250, and a shield60. The finger grip 250 includes outer gripping surfaces or walls 256,and lateral surfaces or walls 255 defining a recess 251 for receivingthe proximal end 93 of the syringe 90. One or more tabs or detents 258extend from the finger grip 250 into the recess 251 for engaging theflange 96 to secure the pre-filled syringe 90 within the guard 10.

Preferably, a pair of tabs 258 are integrally formed along the oppositesubstantially flat walls, for example along outer gripping surfaces s256, extending into the recess 251 (FIG. 16B). The tabs have rampedproximal surfaces 258 a and blunt distal surfaces 258b. Alternatively, asingle tab 258 may be provided along a corner of the recess 251 (FIG.16C), or a pair of tabs 258 may be provided on the lateral surfaces 255(FIG. 16D).

During use, a pre-filled syringe 90 may be introduced into the body 20until the flange 96 begins to enter the recess 251 defined by the fingergrip 250. The flange 96 engages the ramped proximal surfaces 258 a ofthe tabs 258, forcing the tabs 258 radially outward until the flange 96substantially enters the recess 251. The tabs 258 then resilientlyreturn radially in, the blunt distal surfaces 258 b of the tabs 258substantially engaging the proximal end 93 of the pre-filled syringe 90,thereby substantially preventing the pre-filled syringe 90 fromwithdrawing proximally from the body 20. Preferably, the pre-filledsyringe 90 includes an enlarged proximal hub (see FIGS. 15B, 15D) whichabuts a distal surface within the recess 251, thereby preventing thepre-filled syringe 90 from extending distally through the body 20. Inaddition, the substantially rectangular shapes of the finger grip 250and recess 251 require that the pre-filled syringe 90 be inserted in apredetermined orientation, causing a flat edge 96 a of the proximal end93 to abut a wall of the recess to prevent rotational movement of thepre-filled syringe 90. The guard 10 and pre-filled syringe 90 may thenbe used, similar to the embodiments described above, to delivermedication, and thereafter shield the needle (not shown in FIGS.16A-16D) with the shield 60.

Alternatively, as shown in FIGS. 17A-17E, the finger grip 250 mayinclude a latch or cover.260 for enclosing the recess 251 once apre-filled syringe 90 is inserted therein instead of the tabs 258 shownin FIGS. 16A-16D. Preferably, the latch 260 is attached to the fingergrip 250 by a hinge 261, although alternatively, the latch 260 may be aseparate piece adapted to snap under tabs within the recess (not shown).The latch 260 includes an aperture 262 for accommodating the plunger(not shown) of the pre-filled syringe 90, the aperture being preferablydefined by a pair of fingers 264. Preferably, the latch 260 isintegrally formed along a wall (e.g. the lateral wall 255) of the fingergrip 250 and has a slightly curved cross-section. A tab 266 ispreferably integrally formed on and extending inward from the oppositewall (e.g. the opposing lateral wall 55), preferably having a rampedproximal edge 266a and a substantially blunt distal edge 266 b. Thethickness and/or material of the latch 260 preferably renders the latch260 semi-rigid, thereby facilitating its insertion into the recess 251and under the tab 266, as described below.

A pre-filled syringe 90 may be directed into the body 20 until theflange 96 substantially enters the recess 251 and abuts the lowersurface 254 a. The latch 260 may then be folded along the hinge 261until it enters the recess 251. The ramped edge 266 a forces the tab 266radially outward, thereby allowing the latch 260 to enter the recess251. The blunt distal edge 266 b then engages the fingers 264, therebysubstantially enclosing the recess 251 and preventing the pre-filledsyringe 90 from moving proximally from the guard 10 during use.

In a final preferred embodiment, shown in FIGS. 18A-18D, 19 and 20, asyringe guard 10 is provided for receiving relatively small pre-filledsyringes 90, for example conventional 0.5 mL capacity pre-filledsyringes, which include a rigid nose shield or needle protector cap 97having a diameter larger than the diameter of the barrel 92 of thepre-filled syringe 90. The syringe guards described above are lesspreferred for such small pre-filled syringes because such small sizepre-filled syringes would require a relatively small guard which mayrender the devices more difficult or inconvenient to manipulate. Stateddifferently, a predetermined minimum length and/or cross-section (largerthan the length and/or cross-section of the small pre-filled syringe)may be desired for the syringe guard to maximize safe and convenient useof the pre-filled syringe to deliver medication.

Generally, the guard 10 includes a body 20 having a locking mechanism inits proximal end for lockably engaging the proximal end 93 and/or flange96 of the pre-filled syringe 90 received therein, such as the lockingmechanisms described above. Preferably, the locking mechanism issufficiently rigid such that the pre-filled syringe 90 may besubstantially retained within the cavity 26 to prevent axial and/orlateral movement without requiring a collar on the distal end 24 of thebody 20. For example, the finger grip 50 may include a plurality oflocking detents 58 partially defining a slot 57, as shown in FIGS. 18Aand 18B. Alternatively, one or more tabs (not shown) may be providedwithin the recess 51, for example along the inside of the lateral walls55, as described above, for engaging the proximal end 93 of thepre-filled syringe 90.

Turning to FIGS. 18A and 18B, the body 20 generally includes a pair ofrails 28 defining a cavity 26 for receiving a pre-filled syringe (notshown in FIGS. 18A and 18B), similar to the embodiments described above.The rails 28 may have a “C” cross-section as described above, or mayhave a substantially flat shape as shown. Preferably, in addition, theinside surfaces 30 of the rails 28 include one or more semi-rigidmembers or ribs 29 extending from the surfaces 30 into the cavity 26.The ribs 29 are resiliently deflectable to facilitate insertion of thepre-filled syringe 90 and enhance a rigidity characteristic of the body20. Preferably, the ribs 29 are provided in pairs integrally formed inthe rails 28 to at least partially define a diameter or cross-sectionalspace similar to the diameter of the barrel 92 of the syringe 90 (seeFIG. 18D). More preferably, a first set of ribs 29a are provided at ornear the distal end 24 of the body 20, and a second set of ribs 29 b isprovided at or near the proximal end 22. The second or proximal set ofribs 29 b may act as lead-in ribs to guide the pre-filled syringe 90during insertion. Preferably, the lead-in ribs 29 b have substantiallytapered proximal edges 29 c to align the needle cap (not shown).

Turning to FIGS. 18C and 18D, a relatively small pre-filled syringe 90may be inserted into the body 20, the pre-filled syringe 90 including arigid needle protector cap 97 or similar safety cap having a diameterlarger than the barrel 92. When the pre-filled syringe 90 is directeddistally into the proximal end 22 of the body 20, the needle protectorcap 97 engages the ribs 29 as it enters the cavity 26. Because of thesemi-rigid nature of the ribs 29, for example due to the resilience ofinjection molded plastic, the ribs 29 are deflected outward toaccommodate the needle protector cap 97 as it passes distally throughthe cavity 26.

Alternatively, the ribs 29 may be substantially rigid and the rails 28themselves may be sufficiently flexible to deform outward as the needleprotector cap 97 engages the ribs 29 to allow the cap 97 to passdistally through the cavity 26. In such an embodiment, however, thepre-filled syringe 90 may have to be inserted into the body 20 prior todirecting the shield 50 thereon, or the shield 50 may have to besufficiently flexible and resilient to accommodate the expansion of therails.

Once the needle protector cap 97 extends beyond the distal end 24 of thebody 20, the ribs 29 resiliently return to abut or engage the barrel 92of the pre-filled syringe 90, thereby preventing substantial lateralmovement of the pre-filled syringe 90 within the guard 10 during use.

More preferably, the ribs 29 preferably engage the barrel 92 to enhancethe rigidity of the body 20, that is, to prevent the rails 28 from beingdeflected inward which may release the shield 60 from the guardedposition. For example, as can be seen in FIG. 18D, the barrel 92 of thepre-filled syringe 90 has a diameter smaller than the cross-section ofthe cavity 26 in the body 20. After use of the pre-filled syringe 90, asdescribed previously, the shield 60 is directed distally to the guardedposition, wherein the detents 71 engage the pockets 42 to preventproximal movement of the shield 60 which may expose the used needle 95.

Although the rails 28 are substantially rigid, they may be slightlycompressible because of the space between the rails 28 and the barrel92, which may allow inadvertent release of the detents 71 from thepockets 42 and undesired proximal movement of the shield 60. The ribs 29provide additional rigidity, for example by substantially engaging thebarrel 92, to prevent compression of the rails 28 and thereby improvethe safety feature of the shield 60 and cooperating detents 71 andpockets 42.

Alternatively, as shown in FIGS. 19 and 20, the body 20 may include adeflectable cradle or frame 230 for supporting the ribs 229. Preferably,the frame 230 has arms 228 with a curved or semi-circular cross-sectiondefining an inner cavity 226 similar in shape and size to the barrel ofthe small unit dose pre-filled syringe (not shown) to be receivedtherein. The frame 230 is attached or molded to the rails 28 by one ormore support legs or tabs 232. The ribs 229 are then formed along atleast a portion of the frame 230, preferably extending between twoframes 230 as shown. The ribs 229 may have a tapered (FIG. 19), arounded (FIG. 20) or other cross-section for engaging the barrel 92and/or the needle cap 97 of the pre-filled syringe 90.

The deflectable, resilient nature of the frame 230 facilitates theinsertion of the pre-filled syringe 90 being received in the body 20.The arms 228 on the frame 230 may be deflected outward to accommodatethe needle protector cap 97, but resiliently return to engage the barrel92 with the ribs 229, thereby providing additional rigidity for therails 28, as described above.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the appended claims.

1. A guard for a syringe comprising a proximal end and a distal end, alip on the proximal end, and a needle extending from the distal end, theguard comprising: a body for receiving the syringe axially through anopen proximal end of the body, and comprising an open distal end, thebody comprising one or more lateral surfaces defining a recess forreceiving the proximal end of the syringe therein, the one or morelateral surfaces comprising one or more slots for receiving at least aportion of the lip of the syringe therein for substantially permanentlyholding-the syringe to the body; a shield slidably attached to the body,and having open proximal and distal ends, the shield being slidablebetween an unguarded and a guarded position, the needle on the syringeextending through the open distal end in the unguarded position andbeing covered by the shield in the guarded position; and cooperatingdetents on the shield and body for holding the shield in the unguardedand guarded positions.
 2. The guard of claim 1, further comprising afinger hold on the shield.
 3. A guard for a syringe having a needleassociated therewith and the syringe having a lip on a proximal endthereof, the guard comprising: a body for receiving a syringe axiallythrough an open proximal end of the body, and having an open distal endthrough which a needle of a syringe may extend, the proximal end of thebody having a wall enclosing a recess for receiving the proximal end ofa syringe and lip thereof, the recess being provided with slots adaptedto substantially permanently engage a lip on the proximal end of asyringe received in the recess; a shield slidably attached to the body,and having open proximal and distal ends, the shield being slidablebetween an unguarding and a guarding position, said shield being adaptedto permit a needle-on a syringe to extend through the open distal endwhen the shield is in the unguarding position and to cover the shield inthe guarding position; and cooperating detents on the shield and bodyfor holding the shield in the unguarding and guarding positions.
 4. Aguard for a syringe comprising a proximal end and a distal end, a lip onthe proximal end, and a needle extending from the distal end, the guardcomprising: a body comprising a cavity for receiving the syringe axiallytherein through an open proximal end of the body, and comprising an opendistal end; one or more lateral surfaces on the proximal end of the bodydefining a recess for receiving the, proximal end of the syringetherein, the lateral surfaces comprising a mechanism for substantiallypermanently engaging the lip on the proximal end of the syringe receivedin the cavity; a shield slidably attached to the body, and having openproximal and distal ends, the shield being slidable between an unguardedand a guarded position, the needle on the syringe extending through theopen distal end in the unguarded position and being covered by theshield in the guarded position; and cooperating detents on the shieldand body for holding the shield in the unguarded and guarded positions,wherein the locking mechanism comprises locking detents in the lateralsurfaces for engaging the proximal end of the syringe received in thecavity, thereby substantially permanently locking the syringe in thebody.
 5. The guard of claim 4, wherein the locking detents have taperedproximal edges and blunt distal edges for substantially permanentlyreceiving the lip on the syringe thereunder.
 6. The guard of claim 4,wherein the locking detents define slots for receiving the lip therein,thereby preventing the syringe from being removed proximally from thebody.
 7. A syringe comprising: a syringe holding medication comprisingproximal and distal ends, the syringe comprising a needle extending fromthe distal end and a lip on the proximal end; a body comprising a cavityfor receiving the syringe axially therein through an open proximal endof the body, and comprising an open distal end; one or more lateralsurfaces on the proximal end of the body defining a recess for receivingthe proximal ends of the syringe therein, the lateral surfacescomprising a mechanism for engaging the lip to substantially permanentlyencapsulate the syringe in the body; a shield slidably attached to thebody, and having open proximal and distal ends, the shield beingslidable between an unguarded and a guarded position, thereby uncoveringand covering, respectively, the needle on the syringe; and cooperatingdetents on the shield and body for holding the shield in the guarded andunguarded positions, wherein the mechanism comprises detents in thelateral surfaces for engaging the proximal end of the syringe receivedin the cavity, thereby substantially permanently holding the syringe inthe body.
 8. The guard of claim 7, wherein the detents have taperedproximal edges and blunt distal edges for substantially permanentlyreceiving the lip on the syringe thereunder.
 9. The guard of claim 7,wherein the detents define slots for receiving the lip therein, therebypreventing the syringe from being removed proximally from the body. 10.A guard for a syringe, the syringe comprising a proximal end and,adistal end, a lip on the proximal end, and a needle extending from thedistal end, the guard comprising, a body comprising a cavity forreceiving the syringe axially therein through an open proximal end ofthe body, and the body comprising an open distal end, the proximal endof the body including a finger grip, a recess for receiving the proximalend of the syringe therein, and a wall completely encircling theproximal end through which the lip on the proximal end of the syringecan pass, the proximal end of the body substantially permanentlyengaging the lip on the proximal end of the syringe received in thecavity of the body, a shield slidably attached to the body and havingopen proximal and distal ends, the shield being slidable between anunguarded and a guarded position, the needle on the syringe extendingthrough the open distal end in the unguarded position and being coveredby the shield in the guarded position, and cooperating detents on theshield and body for holding the shield in the unguarded and guardedpositions.
 11. The guard of claim 10, wherein the cooperating detentscomprise one or more cooperating detents and detent pockets on the bodyand the shield, at least one of the cooperating detents and detentpockets releasably holding the shield in the unguarded position, and atleast one of the cooperating detents and detent pockets comprising ablunt proximal region for substantially permanently locking the shieldin the guarded position.
 12. The syringe of claim 10, further comprisinga finger ledge on one of the body and the shield.
 13. A guard for asyringe, the syringe comprising a proximal end and a distal end, a lipon the proximal end, and a needle extending from the distal end, theguard comprising, a body comprising a cavity for receiving the syringeaxially therein through an open proximal end of the body, and the bodycomprising an open distal end, the proximal end of the body including afinger grip, a recess for receiving the proximal end of the syringetherein, and a wall completely surrounding the proximal end of the bodythrough which the lip on the proximal end of the syringe can pass, theproximal end of the body substantially permanently engaging the lip onthe proximal end of the syringe received in the cavity of the body, ashield slidably attached to the body and having open proximal and distalends, the shield being slidable between an unguarded and a guardedposition, the needle on the syringe extending through the open distalend in the unguarded position and being covered by the shield in theguarded position, and cooperating detents on the shield and body forholding the shield in the unguarded and guarded positions.
 14. A guardfor a syringe, the syringe comprising a proximal end and a distal end, alip on the proximal end, and a needle extending from the distal end, theguard comprising, a body comprising a cavity for receiving the syringeaxially therein through an open proximal end of the body, and the bodycomprising an open distal end, the proximal end of the body including afinger grip, a recess for receiving the proximal end of the syringetherein, and a wall completely encircling the proximal end of the bodythrough which the lip on the proximal end of the syringe can pass, theproximal end of the body engaging the lip on the proximal end of thesyringe received in the cavity of the body to substantially permanentlyencapsulate the cartridge in the cavity, thereby restraining thecartridge from moving proximally from the cavity, a shield slidablyattached to the body and having open proximal and distal ends, theshield being slidable between an unguarded and a guarded position, theneedle on the syringe extending through the open distal end in theunguarded position and being covered by the shield in the guardedposition, and cooperating detents on the shield and body for holding theshield in the unguarded and guarded positions.
 15. A guard for asyringe, the syringe comprising a proximal end and a distal end, a lipon the proximal end, and a needle extending from the distal end, theguard comprising, a body comprising a cavity for receiving the syringeaxially therein through an open proximal end of the body, and the bodycomprising an open distal end, the proximal end of the body including afinger grip, a recess for receiving the proximal end of the syringetherein, and a wall completely encircling the proximal end of the bodythrough which the lip on the proximal end of the syringe can pass, theproximal end of the body engaging the lip on the proximal end of thesyringe received in the cavity of the body to substantially permanentlyencapsulate the cartridge in the cavity, thereby restraining proximalmovement of the cartridge from the cavity, a shield slidably attached tothe body and having open proximal and distal ends, the shield beingslidable between an unguarded and a guarded position, the needle on thesyringe extending through the open distal end in the unguarded positionand being covered by the shield in the guarded position, and cooperatingdetents on the shield and body for holding the shield in the unguardedand guarded positions.
 16. A guard for a syringe, the syringe comprisinga proximal end and a distal end, a lip on the proximal end, and a needleextending from the distal end, the guard comprising, a body comprising acavity for receiving the syringe axially therein through an openproximal end of the body, and the body comprising an open distal end,the proximal end of the body including a finger grip, a recess forreceiving the proximal end of the syringe therein, and a wallsurrounding the proximal end of the body through which the lip on theproximal end of the syringe can pass, the proximal end of the bodyengaging the lip on the proximal end of the syringe received in thecavity of the body to substantially permanently encapsulate thecartridge in the cavity, thereby restraining the cartridge from movingproximally from the cavity, a shield slidably attached to the body andhaving open proximal and distal ends, the shield being slidable betweenan unguarded and a guarded position, the needle on the syringe extendingthrough the open distal end in the unguarded position and being coveredby the shield in the guarded position, and cooperating detents on theshield and body for holding the shield in the unguarded and guardedpositions.
 17. A guard for a syringe, the syringe comprising a proximalend and a distal end, a lip on the proximal end, and a needle extendingfrom the distal end, the guard comprising, a body comprising a cavityfor receiving the syringe axially therein through an open proximal endof the body, and the body comprising an open distal end, the proximalend of the body including a-finger grip, a recess for receiving theproximal end of the syringe therein, and a wall completely surroundingthe proximal end of the body through which the lip on the proximal endof the syringe can pass, the proximal end of the body engaging the lipon the proximal end of the syringe received in the cavity of the body tosubstantially permanently encapsulate the cartridge in the cavity,thereby restraining the cartridge from moving proximally from thecavity, a shield slidably attached to the body and having open proximaland distal ends, the shield being slidable between an unguarded and aguarded position, the needle on the syringe extending through the opendistal end in the unguarded position and being covered by the shield inthe guarded position, and cooperating detents on the shield and body forholding the shield in the unguarded and guarded positions.
 18. A guardfor a syringe, the syringe comprising a proximal end and a distal end, alip on the proximal end, and a needle extending from the distal end, theguard comprising, a body comprising a cavity for receiving the syringeaxially therein through an open proximal end of the body, and the bodycomprising an open distal end, the proximal end of the body including afinger grip, a recess for receiving the proximal end of the syringetherein, and a wall completely encircling the proximal end of the bodythrough which the lip on the proximal end of the syringe can pass, theproximal end of the body engaging the lip on the proximal end of thesyringe received in the cavity of the body to substantially permanentlyencapsulate the cartridge in the cavity to restrain proximal movement ofthe cartridge from the cavity, a shield slidably attached to the bodyand having open proximal and distal ends, the shield being slidablebetween an unguarded and a guarded position, the needle on the syringeextending through the open distal end in the unguarded position andbeing covered by the shield in the guarded position, and cooperatingdetents on the shield and body for holding the shield in the unguardedand guarded positions.
 19. A guard for a syringe comprising a proximalend and a distal end, a lip on the proximal end, and a needle extendingfrom the distal end, the guard comprising: a substantially rigid bodycomprising a cavity for receiving the syringe axially therein through anopen proximal end of the body, and comprising an open distal end; one ormore lateral surfaces on the proximal end of the, body forming acontinuous wall for receiving the proximal end of the syringe, and oneor more detents extending from the one or more lateral surfaces forengaging the lip to substantially permanently encapsulate the syringe inthe body; a shield slidably attached to the body, and having openproximal and distal ends, the shield being slidable between an unguardedand a guarded position, thereby uncovering and covering, respectively,the needle on the syringe, and cooperating detents on the shield andbody for holding the shield in the unguarded and guarded positions. 20.The guard of claim 19, wherein the one or more detents extend from theone or more lateral surfaces into the recess to capture the lip of thesyringe thereunder when the syringe is received within the cavity. 21.The guard of claim 19, wherein the detents have tapered proximal edgesand blunt distal edges for substantially permanently receiving the lipon the syringe thereunder.
 22. The guard of claim 19, wherein thecooperating detents comprise one or more cooperating detents and detentpockets on the body and the shield, at least one of the cooperatingdetents and detent pockets releasably holding the shield in theunguarded position, and at least one of the cooperating detents anddetent pockets comprising a blunt proximal region for substantiallypermanently locking the shield in the guarded position.
 23. A guard fora syringe comprising a proximal end and a distal end, a lip on theproximal end, and a needle extending from the distal end, the guardcomprising: a body comprising a cavity for receiving the syringe axiallytherein through an open proximal end of the body, and comprising an opendistal end, the proximal end of the body having a wall encircling arecess and a plurality of slots for receiving a portion of the lip ofthe syringe therein for substantially permanently retaining the syringeto the body; a shield slidably attached to the body, and having openproximal and distal ends, the shield being slidable between an unguardedand a guarded position, the needle on the syringe extending through theopen distal end in the guarded position and being covered by the shieldin the guarded position; and cooperating detents on the shield and bodyfor holding the shield in the unguarded and guarded positions.
 24. Theguard of claim 23, wherein the proximal end of the body compriseslocking detents defining the slots.
 25. A guard for a syringe having aneedle associated therewith, the guard comprising: a body for receivinga syringe axially through an open proximal end of the body, and havingan open distal end, the proximal end of the body having a wall forsubstantially encircling a recess for receiving the proximal end of asyringe therein, the proximal end of the body substantially permanentlyengaging a lip on the proximal end of a syringe received in the recessto substantially permanently encapsulate the cartridge in the cavity torestrain proximal movement of the cartridge from the cavity; a shieldslidably attached to the body, and having open proximal and distal ends,the shield being slidable between an unguarding and a guarding position,said shield being adapted to permit a needle on a syringe to extendthrough the open distal end when the shield is in the unguardingposition and to cover the shield in the guarding position; andcooperating detents on the shield and body for holding the shield in theunguarding and guarding positions.
 26. The guard of claim 25, whereinthe proximal end of the body has detents for engaging the proximal endof a syringe received in the recess, the detents having tapered proximaledges and blunt distal edges for substantially permanently receiving alip on a syringe thereunder.
 27. The guard of claim 26, wherein thedetents define slots for receiving at least a portion of the liptherein, thereby substantially preventing a syringe from being removedproximally from the body.
 28. The guard-of claim 25, further comprisinga finger ledge on at least one of the body and the shield.
 29. The guardof claim 28, wherein the finger ledge comprises a finger hold on theshield.
 30. The guard of claim 25, wherein the body has a roundcross-section.